High Speed Dual Fuel Direct Injection Engines With Advanced EGR And Injection Strategies To Reduce The Carbon Dioxide Emissions

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This project intends to demonstrate the potential of using advanced natural gas dual fuel light-duty diesel engines to significantly reduce engine out CO2. This type of engine ingests a fresh charge of air and a quantity of gaseous fuel simultaneously to produce a lean premixed charge. This lean charge is then compressed and near the end of the compression stroke a small quantity of diesel fuel (the pilot fuel) is injected into the cylinder. After a delay period, this pilot diesel fuel then ignites and both the pilot diesel fuel and the lean mixture of gaseous fuel and air combust. By retaining a high compression ratio, thermal efficiencies similar to or higher than conventional diesel engines can be realised at high loads. The proposed work employs an existing research engine at Loughborough University, and this engine will be converted to run on dual fuel using methane as the gaseous fuel. The barrier to the current deployment of dual-fuelling in light-duty engines is a result of the higher engine speeds required for these smaller engines, which result in temporally shorter combustion events. This is a concern for dual-fuel combustion, which typically has a slower combustion than conventional diesel because of its premixed nature and relatively low flame propagation rates. This proposal aims to demonstrate that, through the use of hot exhaust-gas recirculation (EGR) and multiple diesel injections, the dual-fuel combustion rate can be increased to meet the requirements of light-duty diesel engines.Currently the light duty diesel engine sector emit 35MT CO2 per year. If all light-duty diesel vehicles in the UK were converted to dual-fuel natural gas, CO2 emissions could be reduced by up to 7 MT/year. For initial deployment in fleet applications, light-duty dual-fuelled vehicles would reduce CO2 emissions by 20% while reducing fuelling costs; even the cost of installing a fuel delivery system would pay-back in approximately 5 years. These impacts, once the technology has been demonstrated, should be of interest to operators of fleets of light-duty delivery vehicles as well as to major automotive companies.